1. Field of the Invention
The present invention relates to a flat-typed vibration motor capable of receiving a current, with a portion of a lower board having a brush being exposed, thereby increasing its productivity.
2. Description of the Prior Art
Generally, receiving function for receiving a voice or a message is required in communication devices, and in addition, an incoming call notifying function is also required therein. As means for performing the incoming call notifying function, a sounding mode in which a bell or melody is used and a vibration mode which uses a vibration are widely used.
In other words, if a user optionally selects one among incoming notifying functions to employ in notifying of an incoming call, when an incoming call is received, a preset function is started to notify the user of a cellular phone of the incoming call.
Between the incoming call notifying modes, the vibration mode is selected so as not to exert offensive influences on its environment.
In order to notify the user of the incoming call, the sounding mode adopts various kinds of melody or bell inputted to emit the sound by a small sound generation device, while the vibration mode adopts a vibrating force transmitted to a case of the communication device.
The vibrating mode is effected by the vibration motor which is dispersed in the communication device, and a typical example of this vibration motor is a coin-typed or flat-typed vibration motor (so-called pancake motor) including a configuration of a diameter large relative to a thickness thereof, as shown in FIG. 1.
This flat-typed vibration motor comprises a fixing member, i.e., a stator consisting of a magnet 3 and a case, and a rotating member, i.e., a rotor r, and an electrical connection between the stator and the rotor is achieved by a brush 7b. 
Specifically, a lower board 2 with a printed circuit on one surface is attached to an upper surface of a lower case 1 of a circular plate by means of an adhesive, and the doughnut-shaped magnet 3 is attached to an upper surface of the lower board 2 by the same way.
At that time, since the lower board 2 is attached to a portion of the upper surface of the lower case 1, the magnet 3 is significantly attached to the lower board 2 of the lower case 1.
On the other hand, an upper portion of the lower case 1 is covered by an upper case 4, of which has a cap-shaped configuration, and is opened at its lower end. The lower case 1 and the upper case 4 are fixedly engaged to each other by means of a shaft 5 passing through a center of the cases.
A conventional hard board is used as the lower board 2 attached to the lower case 1, and a desired circuit pattern is generally formed on the lower board 2.
The pattern on the lower board 2 is connected to a lead wire 2a to be supplied with a power, and the lead wire is connected to an external power apparatus (not shown) by a welding or is connected to a separate connector.
The vibrating motor comprises a stator and a rotor r rotating around the shaft 5.
The rotor includes an upper board 6 defined by cutting a circular flat plate at a predetermined angle to be eccentrically supported by the shaft, and a commutator 7a formed with a plurality of segments and attached to a lower surface of the upper board.
A plurality of winding coils 8a and a weight 8b are bonded to an upper surface of the rotor r, and insulators 9 made of a typical resin are integrally formed with an upper surface of the upper board 6 by an injection molding except for an bonding surface of the winding coils and the weight.
With the vibration motor constructed as mentioned above, electric power, of which is inputted to the lower board 2 through the lead wire 2a is transmitted to the commutator 7a via the brushes 7b. 
The brushes 7b are consisting of a power input brush and a power output brush, and they are separated one from another by the same angle. The lower ends of each brushes are fixedly connected to the circuit of the lower board, and the upper end of each brushes are brought into sliding contact with the plurality of segments of the commutator 7a. 
Accordingly, the inputted electric power to the commutator 7a is again transmitted to the winding coils 8a via the upper board 6. Then, by the interaction between the winding coils 8a and the magnet 3 which is attached to the lower case, electromagnetic force is generated therebetween to eccentrically rotate the rotor about the shaft. Therefore, the eccentric vibrating force of the rotor is transmitted to the cases through the shaft.
However, in the vibration motor according to the prior art, in order to apply a current to the winding coil 8a provided on the rotor r, one end of the lead wire 2a is connected by welding to the lower board 2, and the other end of the lead wire is connected by welding to a power terminal (not shown) of a unit, onto which the vibration motor is mounted. The welding process may cause the contacted connection to be poor.
In particular, because a worker welds the lead wire 2a by manual, a work efficiency is significantly reduced, and its productivity is also reduced.
Other construction, of which one connector is connected to one end of the lead wire 2a and another connector to be connected to the connector of the lead wire is provided, has been proposed so as to improve the poor contact due to the welding. However, because this method needs several components, a manufacturing cost increases, and the steps for assembling the connectors increases significantly.
It is, therefore, an object of the present invention to provide a flat-typed vibration motor, in which a portion of a lower board provided on a lower case is exposed to be connected for receiving a current without using a welding process, thereby increasing its productivity
To achieve the above object, there is provided a flat-typed vibration motor comprising: a lower case; an upper case covering one side of the lower case; a shaft connecting and supporting the lower case and the upper case; a magnet attached to an upper surface of the lower case; an upper board eccentrically and rotatably supported by the shaft and having a commutator formed with a plurality of segments, the commutator formed in a lower surface of the upper board; a plurality of winding coils spaced at a predetermined angle to each other, and an insulator of a typical resin for fixing the winding coils, the winding coils and the insulator being arranged on one surface of the upper board; and a lower board for covering the lower case, the lower board having one end connected to a brush contacted with the commutator and the other end exposed downwardly from the lower case and comprised of a solder land formed in a regular spacing. Preferably, the lower board is a flexible printed circuit board.
The lower board is electrically connected to a system board including a terminal for applying a power, the terminal having a configuration corresponding to that of the solder land.
The solder land includes a positive pole and a negative pole to receive a power, and is divided into two.